Quantum inelastic collisions between paraexcitons inCu2O

Abstract

A density-dependent loss of optically inactive paraexcitons is measured as a function of temperature over a wide range of densities in ${\text{Cu}}_{2}\text{O}$. At low temperatures, the two-body inelastic collision rate stays at a constant and the extracted collision cross-section diverges. A loss channel cannot be explained classically but is expected in a quantum-mechanical regime. We discuss the repercussion of this loss on the feasibility of achieving Bose-Einstein condensation of paraexcitons in ${\text{Cu}}_{2}\text{O}$.